Solicitors are generally restricted to countries utilizing the UK based system of common law. Before the unification of the Supreme Court in 1873, solicitors practised in the court of Chancery, while attorneys and proctors practised in the common law and ecclesiastical courts respectively.
In the English legal system solicitors have traditionally dealt with any legal matter apart from the conducting proceedings in court (advocacy). The other branch of the English legal profession, a barrister, has traditionally carried out that function and advised on complex areas of law. Barristers would not deal with the public direct.
Solicitors in England and Wales are regulated by the Law Society of England and Wales (which wears the hat of both regulator and union) and in order to become a solicitor must have had a qualifying legal education. The most common methods are a normal undergraduate law degree, or a degree in any subject followed by one year cramming law in a course formerly called the Common Professional Exam and recently renamed the Postgraduate Diploma in Law. Other routes, for example spending time as a clerk to magistrates, or passing exams set by the Institution of Legal Executives (ILEX) are possible. Up to this point a barrister and solicitor have the same education.
Thereafter they split. Solicitors study a one year course called the Legal Practice Course and then must undertake two years apprenticeship with a solicitor, called the training contract (but still widely referred to as 'articles' as in 'articled clerk' by older members of the profession). Once that is complete, the student becomes a solicitor and is 'admitted to the roll'. The 'roll' is a list of people qualified to be a solicitor and is kept on behalf of the 'Master of the Rolls' whose more important job is that he is the head of the Court of Appeal of England and Wales. Solicitors who are being disciplined by the Law Society can be suspended from the roll or even struck off, which prevents them acting as a solicitor.
Moreover, solicitors must pay the Law Society of England and Wales a practising fee each year in order to keep practising. If they do not do this they are 'non-practising' and may not give legal advice to the public (although they can start practising again at will, unlike those struck off).
In the United Kingdom the strict separation between the duties of solicitor and barrister has been partially broken down and solicitors frequently appear not only in the lower courts but (subject to passing a test) increasingly in the higher courts too (such as the High Court of England and Wales and the Court of Appeal). Firms of solicitors now employ their own barristers and solicitor-advocates to do the work, taking it away from the private groups 'sets' or 'chambers' of barristers who formerly did the work. Barristers in turn can now directly instructed by certain organisations such as trade unions.
This breakdown is expected to go further in the next few years, with the government pressing the Bar Council (the Barrister's union/regulator) to allow barristers to deal directly with the public. Solicitors are increasingly taking advantage of their increased rights and so it is to be hoped that the old system (never very efficient) will be swept away in the coming years.